Such apparatuses are commercially available and they use a wide variety of absorbent or filtering materials including textiles, papers, resins, films, and filtering particles, and having a wide variety of properties, with filtering being physical or by ion exchange.
Existing apparatuses have a separation chamber of constant volume and unchanging dimensions, and the filtering material is subjected within such apparatuses to a pressure or a compression factor which is likewise invariable. In general, these apparatuses operate in a medium having a substantially constant ambient temperature, and in normal use of such apparatuses in industry, the absorbent or filtering material is always the same, or, at least, is rarely changed.
When such apparatuses are to be used for making comparative tests or quality control operations on absorbent or filtering materials existing on the market or manufactured in a factory producing absorbent or filtering materials, difficulties arise since the user is obliged to select a separation apparatus capable of accepting the thickness of absorbent or filtering material, and a pressure and a temperature corresponding to the absorbent material that is to be tested, and comparative tests require a plurality of apparatuses giving rise to high costs both when purchasing an installation and while maintaining it, and in addition the apparatuses occupy considerable space even though some of them are little used.
The object of the present invention is to provide an apparatus enabling a large number of absorbent or filtering materials to be used in the apparatus without modifying its structure and regardless of the nature or the properties of the material concerned, said apparatus being simple to use, particularly when changing absorbent or filtering materials, and also being easy to manufacture and being cheap both to purchase and to maintain. In addition, the apparatus should be suitable for performing tests under a wide variety of operating conditions, with respect both to temperature and to pressure.
Proposals have already been made, in particular in European patent specification EP-A-0 152 711, for an apparatus in which the volume and the dimensions of the separation chamber are variable, since one of its end faces is constituted by a piston which is slidably mounted within the enclosure under the effect of drive means. In that document, the liquid to be treated is delivered via the piston rod which is hollow.
However, this apparatus does not satisfy all of the objects of the invention as specified above.
The present invention provides an apparatus for separating at least two elements contained in a liquid or gaseous fluid by means of an absorbent or filtering material, which satisfies the specified objects.